.a-btn_grey{
    width:140px;
    height:140px;
    -webkit-border-radius:50%;
    -moz-border-radius:50%;
    border-radius:50%;
    border: 3px dashed #414f65;
    display:block;
    margin:20px;
    float:left;
    background:#27303e;
    position:relative;
 
}
.a-btn_grey span{
    display:table-cell;
    width:100px;
    height:100px;
    padding:18px;
    text-align:center;
    vertical-align:middle;
    font-size:16px;
    color:#414f65; 
    -webkit-transition:all 0.3s linear;
    -moz-transition:all 0.3s linear;
    -o-transition:all 0.3s linear;
    transition:all 0.3s linear;
}

@keyframes rotate{
    0% { transform: scale(1) rotate(0);}
    50% { transform: scale(0.5) rotate(180deg);}
    100% { transform: scale(1) rotate(360deg);}
}
@-webkit-keyframes rotate{
    0% { -webkit-transform: scale(1) rotate(0);}
    50% { -webkit-transform: scale(0.5) rotate(180deg);}
    100% { -webkit-transform: scale(1) rotate(360deg);}
}
@-moz-keyframes rotate{
    0% { -moz-transform: scale(1) rotate(0);}
    50% { -moz-transform: scale(0.5) rotate(180deg);}
    100% { -moz-transform: scale(1) rotate(360deg);}
}
